Vmfs Partition Table Recovery -

Before you panic or reach for the latest backup (assuming you have one—and you should), take a breath. In many cases, the data on your VMFS datastore is still perfectly intact. The problem is often just the partition table —the map that tells ESXi where the VMFS volume starts and ends on the raw LUN or disk.

partedUtil get /vmfs/devices/disks/naa.6001234567890 If you see Unknown or an empty table, the partition table is missing. Use vmkfstools to scan for VMFS superblocks without relying on the partition table:

vmkfstools -V --config /scratch/config Or more directly: vmfs partition table recovery

partedUtil get /vmfs/devices/disks/naa.6001234567890 If it shows a table but complains about checksum, you may repair the primary from the backup (see recovery section). Method A: Restore partition table from a known backup (Best case) If you have a backup of your ESXi host configuration (e.g., from vicfg-cfgbackup ), you might have saved the partition layouts. Or if you have another identical datastore, compare.

This post is a deep dive into recovering a lost or corrupted VMFS partition table. I’ll cover theory, common causes, diagnostic tools, and step-by-step recovery procedures. A VMFS datastore lives inside a primary partition (type 0xFB for VMFS3 or 0xFC for VMFS5/6) on a disk or LUN. The partition table (usually GPT, sometimes MBR on older systems) sits at the very beginning of the disk (LBA 0) and contains a small entry pointing to the start sector and length of that VMFS partition. Before you panic or reach for the latest

dd if=/vmfs/devices/disks/naa.6001234567890 bs=512 count=1 skip=END_SECTOR_NUMBER | hexdump -C | grep "EFI PART" But skip math is error-prone. Instead, use partedUtil :

When that partition table gets corrupted or deleted, ESXi sees the raw disk as a blank, unpartitioned device. However, the actual VMFS filesystem metadata (heartbeats, file descriptors, block pointers) lives inside the partition, untouched. partedUtil get /vmfs/devices/disks/naa

voma -m vmfs -f /vmfs/devices/disks/naa.6001234567890 This tool is a lifesaver. It will scan the entire device for VMFS structures and report the found start LBA, block size, and file system version. If your disk uses GPT (most modern VMFS5/6), the primary GPT header at LBA 1 might be corrupt, but a backup GPT header resides at the last sector of the disk.